﻿// ConsoleApplication1.cpp : 此文件包含 "main" 函数。程序执行将在此处开始并结束。
//
#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include<stdio.h>

int max3(int x, int y, int z)
{
    int max = x;
    if (max<y )
        max = y;
      if (max<z )
        max = z;
    return max;
}

int main() {
    int a, b, c;
    scanf("%d %d %d", &a, &b, &c);
    printf("%.2f", (float)max3(a + b, b, c) / (max3(a, b + c, c) + max3(a, b, b + c)));
}